How to change radius/weight of curve bezier?
First you need to apply the scale of your object because you must have scaled it in Object mode and it deforms it, so select it and ctrlA.
About the radius, you can either change the radius of the curve vertices or change the radius of the bevel.
For the curve vertices radius, go in Edit mode, select the vertices and altS, or in the N panel (on the right of the 3D View) &gt; Item &gt; Transform &gt; Radius.
For the bevel radius, go in Edit mode, go in the Properties panel &gt; Data &gt; Geometry &gt; and change the Depth.